1. You have a good job (probably - but not necessarily - a professional job)
2. You are willing to spend less money than other people.
And in fact, point 2 is way more important than point 1.
The secret to having more money is not to earn more, it's to spend less.
I'm 36 and I have quit and done what I wanted twice in my life now - once for 2 years I drove AK-Argentina, now I'm well over 2 years driving around Africa. Before both jaunts I earned a mere fraction of what Bay area salaries appear to be. Before Argentina my salary was $48k CAD.
The trick is simply to spend less. Don't upgrade your phone (or don't even have one), don't eat out. Walk or ride to work, no TV, no Netflix, etc. etc. Pretty soon you'll find you have way more money than you actually need, and you can choose to work either part time, or not work at all for a while.
If you were willing to put in 10-15 years of this frugal life, you'd have enough money to never work again, easily.
EDIT: Because everyone always asks how I do it, I wrote a book about how I do this with my life: http://theroadchoseme.com/work-less-to-live-your-dreams